1. Field of the Invention
Technical Domain
This invention relates to a structure for mounting or suspending a turboprop under an aircraft wing.
This type of structure may be used on any type of aircraft comprising turboprops suspended under its wing. In this respect, it is particularly suitable for use on aircraft fitted with turboprops capable of outputting high power, more than 10000 horsepower.
2. Description of the Related Art
On existing aircraft, engines are suspended under or are mounted above the wing by complex Engine Mounting Structures (EMS).
These structures are designed particularly to transmit static and dynamic forces generated by engines, such as weight, thrust or different dynamic forces, to the wing.
In the special case of a turboprop, three main criteria are taken into account to design the associated mounting structure, namely resistance to engine torque, the mass of this structure and finally the limitation to the displacement of the turboprop nozzle relative to the mounting structure.
In prior art, a turboprop is conventionally suspended under an aircraft wing by using a mounting structure comprising a rigid structure provided with an aft under-wing box, and one or several rigid segments arranged in sequence towards the forward end along the longitudinal direction of the engine. As an illustrative example, in this type of so-called statically indeterminate solution, the structure can include two rigid forward segments.
In this configuration, each rigid forward segment has two transverse frames at a spacing from each other, and connected to each other by a plurality of connecting rods, which then jointly form a so-called “lattice structure” with the transverse frames.
This solution is satisfactory for a mounting structure designed to suspend a turboprop within a normal power range, particularly due to its ability to resist the engine torque generated during operation of the associated turboprop.
Nevertheless, recent aircraft development has lead particularly to the use of extremely high power turboprops compared with power values encountered in the past, these power values possibly being more than 10000 horsepower or even more than 13000 horsepower.
Studies carried out showed that considering technical feasibility limits for connecting rods for a conventional lattice type structure, this type of structure cannot resist the entire engine torque generated for such high power values, which can be more than 230000 N.m.